Replace Lena with Hopper (Part IV)

For #884.

With this, all but lena.fli have been replaced. 

I also changed the Travis build order:
```
# Run slow PyPy* first, to give them a headstart and reduce waiting time.
# Run latest 3.x and 2.x next, to get quick compatibility results.
# Then run the remainder.
python:
  - "pypy"
  - "pypy3"
  - 3.4
  - 2.7
  - 2.6
  - "2.7_with_system_site_packages" # For PyQt4
  - 3.2
  - 3.3
```